Xi’an researchers made water-based solar ink particles connect better, yielding certified 12.59% efficiency in laboratory cells

Researchers have found a method that significantly improves the efficiency of organic solar cells.

Nations worldwide are accelerating the deployment of renewable energy infrastructure to meet strict climate regulations.

Despite this green ambition, the manufacturing of most clean energy technologies is not entirely eco-friendly.

The ultimate challenge was raising the energy conversion efficiency of PV cells, which in turn would increase total power generation.

While water-based organic alternatives do exist, they experience limited efficiency, resulting in reduced power conversion.

How did the Xi’an researchers achieve cleaner photovoltaics with a record certified efficiency level?

How green technologies are scaling globally despite not being entirely green

Renewable energy infrastructure is rapidly scaling up worldwide.

Green capacity increased by a record 814 gigawatts globally in 2025.

As for the world’s combined installed solar energy capacity, it surpassed 2,300 gigawatts.

Nations are deploying photovoltaics at scale to meet both rising electricity demands and net-zero decarbonization targets.

In China, for example, photovoltaic power plays an essential role in national climate goals.

Under its 15th Five-Year Plan, the country is targeting a combined 2,800 gigawatts of solar and wind energy.

This will drive renewable generation to 4,000 terawatt-hours by 2030.

By mid-2026, the nation achieved a significant milestone.

Installed solar capacity exceeded 1,288 gigawatts, slightly surpassing coal-fired power generation for the first time.

However, while these technologies help offset carbon emissions, they are still not entirely eco-friendly.

Long before clean power generation, the manufacturing stage of photovoltaic (PV) cells already has a hidden environmental impact.

The hidden environmental costs of standard solar panel production

Photovoltaics have led the global green energy transition, accounting for the highest installed capacity worldwide.

However, clean energy needs have shifted, requiring higher volumes of generation.

As deployment space and permitting became more complex, researchers had to boost output without requiring a bigger footprint.

The ultimate challenge was raising the energy conversion efficiency of PV cells, which in turn would increase total power generation.

Different PV cell designs have significantly improved in this, showing great potential for commercialization.

Unfortunately, silicon solar cell manufacturing carries major environmental trade-offs.

Transforming quartz into silicon requires extreme heat and is very energy-intensive.

Fabrication also relies on toxic chemical solvents.

The handling and disposal of these chemicals risk water and soil contamination.

To address these trade-offs, researchers are creating organic PV cells.

Water-based organic cells have become a particular point of interest, but they face a severe efficiency bottleneck.

This has hindered commercial adoption, but Xi’an Jiaotong University has found a key solution.

Unlocking efficient, eco-friendly solar cells

Different organic solar cells are being explored worldwide, but recent research has highlighted the promise of water-based ones.

Water-based organic PV cells replace toxic chemical solvents by using water to process active ink materials.

Even so, the water often prevents ink nanoparticles from blending, forming barrier layers that block electrical currents.

The Xi’an researchers addressed this by controlling the water-oil interfacial kinetics during nanoparticle formation.

The team was led by Professor Wei Ma and Dr. Zhaozhao Bi from the School of Materials Science and Engineering.

Boosting the efficiency of water-based organic PV cells

The manipulation of microscopic tension prevents clumping, creating a balanced polycrystalline structure.

This enabled the solar ink particles to fuse into a uniform film while drying.

The method helped the team achieve a certified 12.59% power conversion efficiency.

Furthermore, thermal stability also improved under high temperatures.

The breakthrough demonstrates that eco-friendly, water-based manufacturing can match performance standards.

The next step for the Xi’an team is to scale production from small laboratory cells to large-area modules.

Furthermore, long-term outdoor stability testing under real-world weather conditions must also be prioritized.

Should these steps be successful, commercial adoption of water-based organic solar panels could begin within five to seven years.

Ultimately, the newly improved PV cell technology could take the global green transition in a new direction.

The research can be reviewed using: Bi, Z., Wang, K., Liu, C. et al. Water-oil interfacial kinetics control enables water-based organic solar cells with 12.59% certified efficiency. Nat Commun (2026). https://doi.org/10.1038/s41467-026-78233-1